Protective respiratory apparatuses for people are known in principle. They are used, for example, to supply relief forces in emergencies with atmospheric oxygen and corresponding respiratory air. Such protective respiratory apparatuses are, for example, portable systems so that relief forces, for example fire fighters, are supplied with respiratory air even in difficult and adverse ambient conditions.
DE 10 2008 055 700 B4, for example, presents such a protective respiratory apparatus.
It is also known that a respiratory circuit is provided in the case of such protective respiratory apparatuses so that the expired respiratory air at least in part is provided again for the respiratory air that is to be inspired.
In order to be able to guarantee a sufficient vital function for the person, in this connection usually a regeneration step occurs in which CO2 is extracted from the expired respiratory air (for example by absorption).
Subsequently, oxygen from an oxygen reservoir is admixed in order to maintain a sufficient proportion of oxygen in the respiratory air.
The disadvantage of the known solutions for protective respiratory apparatuses is that the respiratory air registers a rise in temperature during use. This is based in particular on the fact that the extraction of CO2, for example by means of an absorption step, results in the respiratory air being heated up as a consequence. This is usually accompanied with a loading of the respiratory air with moisture so that the respiratory air exits known respiratory-air regenerators in a state in which it is heated up and usually saturated with water. Since the respiratory air is guided in a circuit, this would result in an increase in temperature of the respiratory air which is very unpleasant for the user of the protective respiratory apparatus.
In the case of known protective respiratory apparatuses therefore usually a cooling device is used, as it is described, for example, in DE 10 2008 055 700 B4.
Such cooling devices are very expensive and complex to produce and in addition require structural space and also corresponding materials, as a result of which the weight and the volume of the protective respiratory apparatus are increased in an undesirable manner.
Known cooling devices in the form of ice coolers have little flexibility, however, with regard to their variability and their adaptation. The service life of such ice coolers is also limited to the corresponding melting time of the ice arranged therein.